SegmentedControl: Set focus to specific segment?

In my Mac App I have a segmented control for a preference which is assigned during startup. So any segment could be selected.
Now setting the focus to the SegmentedControl does always draw the focus ring to the first segment, only.
A click to another segment does show the focus ring here. How can I set the focus ring to a specific segment?

Even the Sample “Example Projects/Desktop/Controls/SegmentedControl.xojo_binary_project” does it wrong:
Start the sample and click on “Select Earth”
Result: Earth is selected but the focus ring is still on “Sun”

you probably need to set segmentedcontrol.items().selected since a segemented control can have several of items items selected
http://docs.xojo.com/SegmentedControlItem

Well, I do this. So the item is actually selected. It is just the focus ring which stays on the first item (as in the Xojo example, too).

Meanwhile I looked further and I found a setKey handling in NSSegmentedCell. I guess “makePreviousSegmentKey()”/“makeNextSegmentKey()” would help but it seems so that there is no similar call from Xojo available…

I can only do this:

I can’t find a way to move the Focus or even remove the Focus. If I could remove the Focus then maybe is good enough just by using the selected item, right?

This would be Plan B (currently implemented).